This invention relates to windows which appear to have a plurality of individual lites and, in one aspect, multiple-pane, insulated window panel assemblies having such an appearance.
French-style window panels include a plurality of individual lites, an outer frame or casement and smaller frame or sash bars holding individual lites which typically are either rectangular or diamond shaped. Plain window panels have a single glass pane held by an outer frame or casement. French-style window glass panels are preferred for room windows and/or doors in some traditional architectural designs. French-style window panels are substantially more expensive to manufacture than plain windows. Dual-pane, insulated window panel assemblies include two single glass panes separated by and bonded to a peripheral spacer frame to define an insulating air pocket therebetween. In some constructions, this pocket is filled with an inert gas, such as argon or krypton or a mixture of one of these gases and Sf.sub.6, to improve the insulating and/or sound deadening characteristics.
Multiple-pane, insulated windows have been constructed with a plurality of individual panels in an attempt to give the appearance of an authentic divided lite window. In order to accommodate the substantially bulkier insulated window panels, the sash bars for the individual panels usually are about twice as wide as conventional sash bars for authentic divided lite or French-style window. Consequently, the resulting overall panel assembly does not have an authentic appearance. Also, the window units are quite heavy and, for gas-filled units, the risk of developing a gas leak failure is increased because of the number of individual lites. Also, with conventional divided lite windows, the muntin bars extend from the outside to the inside and, therefore, create a path for heat loss.
Different approaches have been used to provide multiple-pane, insulated window panels with the appearance of authentic divided lite or French-style windows. U.S. Pat. No. 3,308,593 discloses the use of intersecting, internal muntin bars disposed in the space between the glass panes. While such an arrangement permits unobstructed washing of the outer panes, the window panel does not look much like an authentic divided lite window. Also, the internal muntin bars are made from a metal and can cause frosting and/or condensation if they come in contact with the glass panes.
U.S. Pat. No. 4,598,520 discloses the use of external muntin bars affixed on the outer side of the glass panes without any internal muntin bars. One standing relatively close to the window of such a construction can observe there is nothing in the space between the glass panes which detracts from its simulated appearance as an authentic divided lite or French-style window.